Organic light-emitting diode (OLED) technology is one of the current research hotspots in flat-panel displays. Compared with a liquid crystal display (LCD), the OLED display has advantages such as low power consumption, low fabrication cost, self-illumination, wide viewing angle and high response speed. Currently in display fields such as cellular phone, tablet computer and digital camera, the OLED display has replaced the conventional LCD.
The LCD controls the brightness using a stabilized voltage. Different from that, the OLED is driven by current, and it requires a stabilized current to control luminance. Usually, for an OLED display, a current is input to the OLED through a driving transistor in a pixel circuit of each pixel, thereby driving the OLED to emit light.
As found by the inventor, the driving transistor spends a lot of time in driving the light-emitting element to emit light, so both the driving transistor and the OLED are in a forward biased state for a long time. As a result, electric characteristic drifts are generated in the driving transistor and the OLED, the service lives of the driving transistor and the OLED are shortened, and the current efficiency is decreased.